1. Field of the Invention
The present invention relates generally to control systems for slipform paving machines and more particularly, but not by way of limitation, to a system for controlling the position of the slipform paving machine while simultaneously controlling changes in paving width as the machine moves forward during a paving operation.
2. Description of the Prior Art
In construction machines for forming structures on a ground surface, such as a concrete slipform paving machine, important factors include the control of the height of the working implements and thus the grade or height of the concrete structure being molded, and the control of the steering direction of the machine.
Such slipform paving machines typically take a reference reading from a stringline which has been placed on one or both sides of the intended path of the machine. In the past, when it has been desired to create a molded concrete structure having a transition from one structure width to a second structure width, two stringlines have been laid out on either side of the desired path of the machine, and the change in width of the concrete structure is created by varying the width between the two stringlines.
Another previously used technique is to have a single stringline on one side of the slipform paving machine, and to manually telescope the machine to control changes in width on the second side of the machine. In this case the height on the second side might be controlled by a slope sensor.
There is a continuing need for improved systems to allow for transition in paving width during a slipform paving operation.